blob: f9c789f540408d7fd0c4c337ad8d58917e7c30d0 [file] [log] [blame]
/*
* Copyright (c) 2018-2021, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <assert_macros.S>
#include <asm_macros.S>
#include <assert_macros.S>
#include <bl31/ea_handle.h>
#include <context.h>
#include <lib/extensions/ras_arch.h>
#include <cpu_macros.S>
#include <context.h>
.globl handle_lower_el_ea_esb
.globl handle_lower_el_async_ea
.globl enter_lower_el_sync_ea
.globl enter_lower_el_async_ea
/*
* Function to delegate External Aborts synchronized by ESB instruction at EL3
* vector entry. This function assumes GP registers x0-x29 have been saved, and
* are available for use. It delegates the handling of the EA to platform
* handler, and returns only upon successfully handling the EA; otherwise
* panics. On return from this function, the original exception handler is
* expected to resume.
*/
func handle_lower_el_ea_esb
mov x0, #ERROR_EA_ESB
mrs x1, DISR_EL1
b ea_proceed
endfunc handle_lower_el_ea_esb
/*
* This function forms the tail end of Synchronous Exception entry from lower
* EL, and expects to handle Synchronous External Aborts from lower EL and CPU
* Implementation Defined Exceptions. If any other kind of exception is detected,
* then this function reports unhandled exception.
*
* Since it's part of exception vector, this function doesn't expect any GP
* registers to have been saved. It delegates the handling of the EA to platform
* handler, and upon successfully handling the EA, exits EL3; otherwise panics.
*/
func enter_lower_el_sync_ea
/*
* Explicitly save x30 so as to free up a register and to enable
* branching.
*/
str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
mrs x30, esr_el3
ubfx x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH
/* Check for I/D aborts from lower EL */
cmp x30, #EC_IABORT_LOWER_EL
b.eq 1f
cmp x30, #EC_DABORT_LOWER_EL
b.eq 1f
/* Save GP registers */
stp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
stp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
stp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
/* Get the cpu_ops pointer */
bl get_cpu_ops_ptr
/* Get the cpu_ops exception handler */
ldr x0, [x0, #CPU_E_HANDLER_FUNC]
/*
* If the reserved function pointer is NULL, this CPU does not have an
* implementation defined exception handler function
*/
cbz x0, 2f
mrs x1, esr_el3
ubfx x1, x1, #ESR_EC_SHIFT, #ESR_EC_LENGTH
blr x0
b 2f
1:
/* Test for EA bit in the instruction syndrome */
mrs x30, esr_el3
tbz x30, #ESR_ISS_EABORT_EA_BIT, 3f
/*
* Save general purpose and ARMv8.3-PAuth registers (if enabled).
* If Secure Cycle Counter is not disabled in MDCR_EL3 when
* ARMv8.5-PMU is implemented, save PMCR_EL0 and disable Cycle Counter.
*/
bl save_gp_pmcr_pauth_regs
#if ENABLE_PAUTH
/* Load and program APIAKey firmware key */
bl pauth_load_bl31_apiakey
#endif
/* Setup exception class and syndrome arguments for platform handler */
mov x0, #ERROR_EA_SYNC
mrs x1, esr_el3
bl delegate_sync_ea
/* el3_exit assumes SP_EL0 on entry */
msr spsel, #MODE_SP_EL0
b el3_exit
2:
ldp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
ldp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
ldp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
3:
/* Synchronous exceptions other than the above are assumed to be EA */
ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
no_ret report_unhandled_exception
endfunc enter_lower_el_sync_ea
/*
* This function handles SErrors from lower ELs.
*
* Since it's part of exception vector, this function doesn't expect any GP
* registers to have been saved. It delegates the handling of the EA to platform
* handler, and upon successfully handling the EA, exits EL3; otherwise panics.
*/
func enter_lower_el_async_ea
/*
* Explicitly save x30 so as to free up a register and to enable
* branching
*/
str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
handle_lower_el_async_ea:
/*
* Save general purpose and ARMv8.3-PAuth registers (if enabled).
* If Secure Cycle Counter is not disabled in MDCR_EL3 when
* ARMv8.5-PMU is implemented, save PMCR_EL0 and disable Cycle Counter.
*/
bl save_gp_pmcr_pauth_regs
#if ENABLE_PAUTH
/* Load and program APIAKey firmware key */
bl pauth_load_bl31_apiakey
#endif
/* Setup exception class and syndrome arguments for platform handler */
mov x0, #ERROR_EA_ASYNC
mrs x1, esr_el3
bl delegate_async_ea
/* el3_exit assumes SP_EL0 on entry */
msr spsel, #MODE_SP_EL0
b el3_exit
endfunc enter_lower_el_async_ea
/*
* Prelude for Synchronous External Abort handling. This function assumes that
* all GP registers have been saved by the caller.
*
* x0: EA reason
* x1: EA syndrome
*/
func delegate_sync_ea
#if RAS_EXTENSION
/*
* Check for Uncontainable error type. If so, route to the platform
* fatal error handler rather than the generic EA one.
*/
ubfx x2, x1, #EABORT_SET_SHIFT, #EABORT_SET_WIDTH
cmp x2, #ERROR_STATUS_SET_UC
b.ne 1f
/* Check fault status code */
ubfx x3, x1, #EABORT_DFSC_SHIFT, #EABORT_DFSC_WIDTH
cmp x3, #SYNC_EA_FSC
b.ne 1f
no_ret plat_handle_uncontainable_ea
1:
#endif
b ea_proceed
endfunc delegate_sync_ea
/*
* Prelude for Asynchronous External Abort handling. This function assumes that
* all GP registers have been saved by the caller.
*
* x0: EA reason
* x1: EA syndrome
*/
func delegate_async_ea
#if RAS_EXTENSION
/*
* Check for Implementation Defined Syndrome. If so, skip checking
* Uncontainable error type from the syndrome as the format is unknown.
*/
tbnz x1, #SERROR_IDS_BIT, 1f
/*
* Check for Uncontainable error type. If so, route to the platform
* fatal error handler rather than the generic EA one.
*/
ubfx x2, x1, #EABORT_AET_SHIFT, #EABORT_AET_WIDTH
cmp x2, #ERROR_STATUS_UET_UC
b.ne 1f
/* Check DFSC for SError type */
ubfx x3, x1, #EABORT_DFSC_SHIFT, #EABORT_DFSC_WIDTH
cmp x3, #DFSC_SERROR
b.ne 1f
no_ret plat_handle_uncontainable_ea
1:
#endif
b ea_proceed
endfunc delegate_async_ea
/*
* Delegate External Abort handling to platform's EA handler. This function
* assumes that all GP registers have been saved by the caller.
*
* x0: EA reason
* x1: EA syndrome
*/
func ea_proceed
/*
* If the ESR loaded earlier is not zero, we were processing an EA
* already, and this is a double fault.
*/
ldr x5, [sp, #CTX_EL3STATE_OFFSET + CTX_ESR_EL3]
cbz x5, 1f
no_ret plat_handle_double_fault
1:
/* Save EL3 state */
mrs x2, spsr_el3
mrs x3, elr_el3
stp x2, x3, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
/*
* Save ESR as handling might involve lower ELs, and returning back to
* EL3 from there would trample the original ESR.
*/
mrs x4, scr_el3
mrs x5, esr_el3
stp x4, x5, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
/*
* Setup rest of arguments, and call platform External Abort handler.
*
* x0: EA reason (already in place)
* x1: Exception syndrome (already in place).
* x2: Cookie (unused for now).
* x3: Context pointer.
* x4: Flags (security state from SCR for now).
*/
mov x2, xzr
mov x3, sp
ubfx x4, x4, #0, #1
/* Switch to runtime stack */
ldr x5, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
msr spsel, #MODE_SP_EL0
mov sp, x5
mov x29, x30
#if ENABLE_ASSERTIONS
/* Stash the stack pointer */
mov x28, sp
#endif
bl plat_ea_handler
#if ENABLE_ASSERTIONS
/*
* Error handling flows might involve long jumps; so upon returning from
* the platform error handler, validate that the we've completely
* unwound the stack.
*/
mov x27, sp
cmp x28, x27
ASM_ASSERT(eq)
#endif
/* Make SP point to context */
msr spsel, #MODE_SP_ELX
/* Restore EL3 state and ESR */
ldp x1, x2, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
msr spsr_el3, x1
msr elr_el3, x2
/* Restore ESR_EL3 and SCR_EL3 */
ldp x3, x4, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
msr scr_el3, x3
msr esr_el3, x4
#if ENABLE_ASSERTIONS
cmp x4, xzr
ASM_ASSERT(ne)
#endif
/* Clear ESR storage */
str xzr, [sp, #CTX_EL3STATE_OFFSET + CTX_ESR_EL3]
ret x29
endfunc ea_proceed